Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Mount Holly New Jersey
827 PM EDT Mon Oct 24 2016
high pressure near Hudson Bay Canada will build closer to our region
through mid week. A warm front on Thursday will be followed by a
cold front Thursday night as low pressure redevelops from near Lake
Erie Thursday to Long Island Friday morning. Weak high pressure
quickly follows Friday night before low pressure and its associated
frontal systems cross the mid Atlantic states Saturday. High
pressure will become dominant over our area by next Monday.
Near term /until 6 am Tuesday morning/...
a relatively quiet night expected tonight across the area. Skies
have clear out in all except the furthest north/west areas. Other clouds
may begin increasing across the northern areas as we approach
daybreak Tuesday. Also, with these advancing clouds, it is
possible for some sprinkles or flurries to occur across our far
northern areas as some enhanced moisture/lift moves into the area
within the northwest flow. Any precipitation amounts are expected
to be light.
Winds have dropped off from the gusty condition earlier. We do
expect the winds to remain light overnight, but probably not go
calm. This should keep the atmosphere from cooling as much as it
Temperatures will cool significantly tonight compared to last night
with widespread 30s, and some 40s. However, with the expected wind
and possible increase in clouds late, we do are not expecting widespread
frost, so we do not anticipate a frost advisory for tonight/Tuesday
morning at this time.
Short term /6 am Tuesday morning through 6 PM Tuesday/...
there could continue to be some sprinkles/flurries at the start of
the day Tuesday due to the enhanced moisture/lift across the area
within the northwest flow. Any precipitation should dissipate
through the morning, however, clouds cover should expand and
increase in coverage across the area during the day.
Winds will again become gusty through the day with gusts reaching 25-
30 mph at times across the area. With the winds, it will feel much
cooler than the actual air temperature with is expected to be mostly
in the 50s, with 40s across the far northern areas.
Long term /Tuesday night through Monday/...
500mb: the cold trough over the northeast USA weakens to the
Maritimes Wednesday. A strong short wave over the Great Lakes
region moves off the mid Atlantic coast Friday, with a following
short wave in the Dakotas moving to mid Atlantic coast Sunday.
Temperatures: the first 23 days of October have averaged nearly 4
degrees above normal. The midweek cold will Dent this above normal
departure but after all 31 days of reality have occurred, the
month as a whole should still average 2 to 3 degrees warmer than
normal. Calendar day averages Wednesday and Thursday should be 4
to 8 degrees below normal. Temperatures Friday and Saturday will
probably average a bit above normal, then cool to near normal
Sunday and Monday.
Forecast basis: unless otherwise noted, a 50 50 blend of the 12z/24
GFS/NAM MOS guidance Tuesday night-Wednesday night, thereafter the
12z/24 GFS mexmos Thursday which was modified warmer i95 sewd for
a 6pm Max temp with probability of precipitation modified 14% higher in accordance with
multimodel consensus and 12z/24 gefs 12 hr pop for .10. Thereafter,
the 15z/24 wpc guidance was applied almost verbatim Thursday
night- Monday. The 12z European model (ecmwf) was toned down in its extremes (caa
Friday and waa for sunday) as it was not in good agreement with
the Meeker looking UK/GFS/ggem.
Tuesday night...frost freeze expected over much of the non urban
region of eastern PA and NJ, probably ending the growing season from
the Lehigh Valley eastward into much of central and northern New Jersey.
This is likely to be the coldest night of the season so far for many
locations. However, record lows are not expected. Mostly clear with
northwest winds decoupling after 10 PM and becoming nearly calm toward
dawn. Npw is posted. Confidence: above average.
Wednesday...highs on Wednesday should be about 1 or 2 degrees
lower than Tuesday, or 5 to 10 degrees below normal. Northwest
winds becoming north with mostly sunny skies (bands of thin
cirrus). Confidence: average
Wednesday night through Thursday...most of the 12z deterministic
models (excluding the NAM on its much slower arrival of rain) have
come into closer agreement with the more progressive timing of the
GFS. The good news with this solution is that cloud cover should
increase rather early on Wednesday night, limiting radiational
cooling (and also consequently making frost unlikely except in a
few of the traditional strong radiators prior to midnight). The
bad news is that even so, precip arriving ahead of the surface
warm front due to warm air advection aloft and a mid level short
wave trough, should be a wintry mix across the southern Poconos
and northwest New Jersey. Sref probs for 1 inch of snow are 20-30 percent. We
couldn't use the 12z/24 NAM prob of frozen pcpn, since it was so
slow with its pcpn onset. Therefore, presuming arrival of the pcpn
between 4 am and 10 am Thursday, there would be some snow, sleet
and freezing rain with a pretty good chance of slippery travel in
the higher terrain of Sussex and Monroe counties. We did not Post
snow and ice maps this evening since we are still in Chancy
occurrence for wintry pcpn, but we could see half an inch of snow
in the kmpo-High Point New Jersey area early Thursday if pcpn onset is
still arriving near dawn. Additionally, there could be a few
hundredths of an inch of ice...but again we're talking 60 hours
out with lack of model agreement. Social media has a Post on this
and the severe weather potential statement continues to highlight. It "may" be a brief advisory
situation with rising temperatures ending the hazard risk by noon.
Wpc and multiple ensemble guidance offer widespread one half inch of
rain to our area, especially PA and New Jersey where there is a chance of
isolated 1 inch of beneficial rainfall. There is also a small chc
of a thunderstorm late Thursday near and south of phl and have
gridded slight chance there. Southerly winds may become gusty 25
kt late in the day. Confidence: average.
Thursday night...since the arrival of the precip has accelerated
in the past two days of modeling, it will probably lead to the
rain quickly ending Thursday evening. Patchy fog may follow for a
time overnight but its not been gridded-forecast. Confidence:
Friday...a short wave ridge slides over the region through the
day, leading to partly sunny skies and seasonable temps but breezy
with northwest winds gusting to 25 mph. The ec is colder than the
GFS/ggem with its 2m temps so confidence on temps Friday is below
Saturday...low pressure and a frontal system is forecast cross
the area with scattered showers expected, and possibly a gusty low
top thunderstorm as swi's are near zero, ki 30-34, and tt near
50. 850 winds are modeled near 40kt, 700 winds 40-50 kt.
Sunday and Monday...considerable model variability. The thinking
right now is northwest winds and dry but confidence is a little
less than average on the outcome. Relied totally on the 15z wpc
Aviation /01z Tuesday through Saturday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.
The following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.
VFR conditions expected overnight. Clouds have decreased across
the area from earlier today. More clouds will arrive across the
north/west areas later tonight.
Winds have diminished from earlier, but remain mostly in the 5 to
15 knots range this evening. More gusts will return Tuesday with
gusts 20-25 knots again, with some locally higher gusts 25-30
Tuesday night and Wednesday...VFR. Northwest winds Tuesday
night and Wednesday become north Wednesday afternoon.
Wednesday night and Thursday...ceilings will lower to MVFR (with
localized ifr) by day break Thursday. Visibility restrictions possible
with periods of rain Thursday into Thursday evening. Ice pellets may
briefly be mixed with the rain at kabe. East to southeast winds
Wednesday night becoming southerly late in the day and may gust 25
kts at kphl, kilg kacy and kmiv. Small chance of a tstm south of
phl late in the day or evening.
Thursday night...lingering MVFR or IFR conds in ending rain/drizzle
with stratus/fog possibly lingering through the night. Southwest
wind turns light northwest.
Friday...becoming VFR early in the day with a gusty northwest wind
to 25 kt in the afternoon.
Saturday...VFR cigs possibly lowering to MVFR conditions in scattered
showers (isolated tstm?). southwest winds may be gusty to 25 kt.
Small Craft Advisory remains in place for tonight and has been
extended into Tuesday as winds are expected to continue to gust
25- 30 knots across the waters tonight into Tuesday. Wind gusts on
the Delaware Bay may drop below 25 knots overnight, but are
expected on increase again on Tuesday.
Tuesday night...Small Craft Advisory lingers in the evening on the Atlantic waters. No
headline after midnight as the northwest wind probably diminishes with
gusts at or below 20 kts after midnight.
Wednesday...no headline. Northwest wind with gusts under 15 kt
becoming northerly during the afternoon.
Thursday...gusty southerly winds are expected to increase to
25 or 30kt late in the day with an Small Craft Advisory likely.
Friday...northwest winds should gust to 25 kt, especially in the
afternoon when an Small Craft Advisory may still be needed.
our forecast indicates October should average at least 2 to 3 degrees
above normal for phl and Abe. Some of the recent forecasts have
been colder and that may mean phl and Abe slip to around 20th
warmest October on record, which is only noteworthy in that the
excessive monthly warmth of July, August, September eased in October.
Will reevaluate this afternoon and Tuesday. The colder scenario
than a week ago still has doubt and so we'll try to be more definitive
late Tuesday regarding around 15th or around 20th warmest October.
Not sure if anyone noticed, but showers early this morning, along
and north of i78 deposited measurable in many areas from kabe and
khzl northeastward. .06 at kabe, .23 at fwn, .11 mpo.
From the cocorahs observers: New Jersey
J-mc-23 : Hopewell TWP 4.6 SW * : 0.44 / mm / mm / mm
New Jersey-ss-7 : Hardyston TWP 3.2 southeast * : 0.29 / mm / mm / mm
New Jersey-ss-8 : Wantage TWP 2.4 SW * : 0.28 / 0.0 / 0.0 / mm
New Jersey-bg-30 : Oakland 1.0 east-southeast * : 0.24 / mm / mm / mm
New Jersey-ps-21 : West Milford TWP 2.5 south-southeast * : 0.24 / mm / mm / mm
New Jersey-bg-29 : Oakland 0.2 west-northwest * : 0.23 / 0.0 / 0.0 / mm
New Jersey-bg-23 : Oakland 0.9 south-southeast * : 0.22 / mm / mm / mm
New Jersey-MN-51 : Rumson 0.5 NE * : 0.22 / mm / mm / mm
New Jersey-ss-3 : Vernon TWP 1.7 north * : 0.21 / mm / mm / mm
New Jersey-bg-10 : River Vale TWP 1.5 S * : 0.20 / mm / mm / mm
New Jersey-ps-25 : Bloomingdale 0.7 south-southeast * : 0.18 / mm / mm / mm
New Jersey-MS-18 : Jefferson TWP 2.4 east-northeast * : 0.17 / mm / mm / mm
New Jersey-cm-12 : Woodbine 5.1 NE * : 0.10 / mm / mm / mm
New Jersey-ss-1 : Andover TWP 1.7 west * : 0.10 / mm / mm / mm
New Jersey-bg-39 : River Edge 0.4 north-northeast * : 0.09 / mm / mm / mm
New Jersey-MS-83 : Washington TWP 2.8 west * : 0.09 / mm / mm / mm
New Jersey-hn-15 : Flemington 0.3 east * : 0.06 / 0.0 / mm / mm
New Jersey-mc-30 : Hopewell TWP 3.9 southeast * : 0.06 / mm / mm / mm
New Jersey-hn-1 : Califon 0.6 northwest * : 0.05 / mm / mm / mm
New Jersey-hn-12 : Holland TWP 2.6 north-northeast * : 0.05 / mm / mm / mm
New Jersey-wr-1 : Greenwich TWP 1.6 S * : 0.05 / mm / mm / mm
New Jersey-bg-3 : Tenafly 1.3 west * : 0.04 / mm / mm / mm
New Jersey-MS-3 : Morris TWP 0.8 northwest * : 0.04 / mm / mm / mm
New Jersey-MS-21 : Randolph TWP 0.8 west * : 0.04 / mm / mm / mm
New Jersey-wr-5 : Hackettstown 0.8 west * : 0.04 / mm / mm / mm
New Jersey-wr-17 : Mansfield TWP 2.6 west-northwest * : 0.04 / mm / mm / mm
New Jersey-wr-21 : Washington 0.6 east-northeast * : 0.04 / mm / mm / mm
New Jersey-hn-18 : Clinton TWP 3.9 north * : 0.03 / mm / mm / mm
New Jersey-hn-21 : Lebanon 2.8 north * : 0.03 / mm / mm / mm
New Jersey-hn-31 : Frenchtown 0.5 north * : 0.03 / mm / mm / mm
New Jersey-MS-6 : Rockaway 0.4 north-northwest * : 0.03 / mm / mm / mm
New Jersey-sm-31 : Peapack-Gladstone 1.3 nne* : 0.03 / mm / mm / mm
New Jersey-wr-32 : Washington 0.3 south-southeast * : 0.03 / mm / mm / mm
New Jersey-es-19 : West Caldwell TWP 1.3 NE * : 0.02 / mm / mm / mm
New Jersey-mc-27 : Hopewell TWP 2.4 northwest * : 0.02 / mm / mm / mm
New Jersey-MD-38 : Edison TWP 1.9 north * : 0.02 / mm / mm / mm
New Jersey-MD-60 : Matawan 1.1 west-southwest * : 0.02 / mm / mm / mm
New Jersey-MS-11 : Boonton 0.6 northwest * : 0.02 / mm / mm / mm
New Jersey-MS-31 : Denville TWP 2.0 north-northeast * : 0.02 / mm / mm / mm
New Jersey-MS-40 : Chatham 0.6 northwest * : 0.02 / mm / mm / mm
New Jersey-MS-49 : Florham Park 0.2 west-northwest * : 0.02 / mm / mm / mm
New Jersey-MS-71 : Denville TWP 1.5 east-southeast * : 0.02 / mm / mm / mm
New Jersey-MS-82 : Mendham 1.5 west * : 0.02 / mm / mm / mm
New Jersey-ps-12 : Little Falls TWP 0.5 west-northwest * : 0.02 / 0.0 / mm / mm
New Jersey-sm-26 : Franklin TWP 3.1 NE * : 0.02 / mm / mm / mm
New Jersey-sm-33 : Hillsborough TWP 2.4 northwest * : 0.02 / mm / mm / mm
New Jersey-un-10 : New Providence 0.8 east-southeast * : 0.02 / mm / mm / mm
New Jersey-bg-15 : North Arlington 0.7 west-northwest * : 0.01 / mm / mm / mm
New Jersey-bg-18 : Palisades Park 0.2 west-northwest * : 0.01 / mm / mm / mm
New Jersey-hn-42 : Lambertville 0.7 south-southeast * : 0.01 / mm / mm / mm
New Jersey-mc-44 : Princeton 2.3 east * : 0.01 / mm / mm / mm
New Jersey-MS-2 : Long Hill TWP 1.2 south-southeast * : 0.01 / mm / mm / mm
New Jersey-sm-1 : Hillsborough TWP 4.7 east-southeast * : 0.01 / mm / mm / mm
New Jersey-sm-34 : Bridgewater TWP 1.6 south-southeast * : 0.01 / mm / mm / mm
New Jersey-sm-61 : Manville 0.3 south-southwest * : 0.01 / mm / mm / mm
PA-Mt-5 : Pottstown 0.6 southeast * : 0.17 / mm / mm / mm
PA-Mt-93 : Pennsburg 0.5 east * : 0.10 / mm / mm / mm
PA-ch-34 : Modena 1.1 north-northeast * : 0.09 / mm / mm / mm
PA-LH-17 : Schnecksville 1.7 east-northeast * : 0.08 / mm / mm / mm
PA-MN-11 : Saylorsburg 2.7 east-northeast * : 0.07 / mm / mm / mm
PA-cb-16 : Jim Thorpe 1.1 north-northeast * : 0.06 / mm / mm / mm
PA-cb-18 : Lehighton 3.3 west-southwest * : 0.06 / mm / mm / mm
PA-MN-13 : Saylorsburg 2.8 west * : 0.06 / mm / mm / mm
PA-NH-12 : Bethlehem 1.8 northwest * : 0.06 / mm / mm / mm
PA-LH-5 : Schnecksville 2.7 SW * : 0.05 / mm / mm / mm
PA-LH-16 : Bethlehem 1.4 west-southwest * : 0.05 / mm / mm / mm
PA-NH-8 : Martins Creek 0.2 east * : 0.05 / mm / mm / mm
PA-br-8 : reading 1.2 SW * : 0.04 / mm / mm / mm
PA-br-21 : Alburtis 4.7 SW * : 0.04 / mm / mm / mm
PA-ch-35 : Phoenixville 2.9 west * : 0.04 / mm / mm / mm
PA-br-25 : Hamburg 0.7 north-northwest * : 0.02 / 0.0 / 0.0 / 0.00
PA-ch-42 : Berwyn 0.7 west-northwest * : 0.01 / mm / mm / mm
PA-Mt-78 : Blue Bell 0.8 NE * : 0.01
PA...freeze watch from late Tuesday night through Wednesday morning
New Jersey...freeze watch from late Tuesday night through Wednesday morning
Delaware...freeze watch from late Tuesday night through Wednesday morning
Maryland...freeze watch from late Tuesday night through Wednesday morning
Marine...Small Craft Advisory until 11 PM EDT Tuesday for anz450>455.
Small Craft Advisory until 6 PM EDT Tuesday for anz430-431.